Let's Make Robots!

Obstacle Detector Ultrasound

Navigate around via Ultrasound Sensors
Mega.jpg213.58 KB
Robo_Explorer.zip1.23 KB

I call this robot Explorer :) This can decide its own path using SRF05 ultra sound sensor. Its primary path is going forward, but if it finds obstacle within 20cm distance, it checks right and left. By comparing the distance of the obstacles in both right and left (if present) it decides its path. A 16x2 LCD has been used to display the information about what the robot is doing. The brain of this robot is an Arduino Mega 2560, I know same thing could be done using the UNO or just the ATmega8. But just tried with the Mega :D To tell about the sensor, SRF05 is one of the best ultra sound sensors I've used so far, I meant comparing to SRF04 or whatever. This is a complete Arduino project, compiler was Arduino as well.

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That looks interesting.

Could you tell us more about the way you powered all this?

I'm not familiar with the Mega: did it have some independant VIn ?

Yes it has an independant Vin and supports from 7V to 12V, it has integrated voltage regulator on board and regulates the voltage to 5V. So you can use 9V battries. Or if you want to supply just 5V, you need to use the USB port of the Mega, in that case you have to use external voltage regulator, I used 7805A and its common and available.

It has 2 gear motors and a servo which drain a lot of power, this is why I made a different circuit to supply power to these motors. Supplying power to these things form Arduino may damage the Arduino, even if it works, they'll get not enough power. So it is better to supply power from a different source. I always prefer different power sources for Arduino/MCU and the other components, ie. the motors or sensors :)

what I don't get is if you used:

-  only one 9V then one connection on Vin for motors and a separate regulator to 5V for the Mega.

- 2 separate 9V one on the Vin, the second on the 5V regulator.

But don't worry, that's just me and my too simple DFRobot 4WD with a Romeo board.

I have to learn back my eletronics knowledge from college :)


I used a 9V source for the Arduino mega and the other source to power the Motors, I've attached a comparable circuit design with it for your convenience :)

I haven't shown capacitors, but its good to use capacitors. And to supply power to the motors, I've used 2 9V battries in parallel. Please check the design in the top.

Thanks for the schema, it really helps.

can you published your sketch ?

Please download the zip file! You might need some modifications :)

Thank you so much for all the shared data. It helps me a lot to understand what I can plan next with my very basic 4WD platform.

It looks like you managed the turn in a better way than me.

My problem is very common: I can't just apply reverse orders on left and right side like a tank ;)

From what I read in your sketch, you have an individual control on each motor ?

I started with a Romeo board that includes two DC Motor Terminals. Maybe it's time for me to learn how to build a H-Bridge :)


Yes it has individual control on each motor, you don't have build an H-Bridge by yourself. You can use L293D. :)

Is that a Plexiglass sheet for the chassis? If so, how did you drill bolt/screw holes without cracking it? Good work by the way.